Close relations, especially romantic partners, can exert profound influence on alcohol use both in everyday life and in treatment contexts. However, the specific mechanisms underlying these effects are not well understood. Elucidating the nature of these interpersonal processes and their role in the maintenance or reduction of high- risk drinking behavior is crucial to addressing problematic alcohol use in romantic relationships. Based on previous models of social control (i.e., influence, regulation) of health behavior, the nature of the social control strategy (i.e., overt, covert), as well as the recipient?s emotional and behavioral responses to that strategy, are relevant constructs that will be examined. The proposed Mentored Research Scientist Award (K01) entails structured training and research activities that will enable the applicant (Dr. Fillo) to examine the nature, use, and relative effectiveness of the full range of social control strategies used among romantic partners aimed at reducing high-risk drinking behavior. A long-term career goal of the candidate is to establish an independent research program investigating the psychosocial mechanisms linking close relationships and high-risk alcohol use, and this award is a critical initial step toward that goal. The candidate will be mentored in professional development (i.e., responsible conduct of research, grantsmanship, conference presentations) and receive extensive training in three key areas: 1) alcohol-related influence processes in close relationships, 2) measure development and validation techniques, and 3) intensive longitudinal methods and data analysis. The candidate proposes a three-phase project using samples of heavy drinking adults in committed, romantic relationships. A comprehensive measure of social control strategies will be adapted from existing measures and prior qualitative research, supplemented with items derived from focus groups (Study 1), and validated using online survey methodology (Study 2). In Study 3, the use and relative effectiveness of overt and covert social control strategies among romantic partners will be prospectively examined as they naturally unfold using daily diary methods. It is hypothesized that covert social control strategies can effectively influence partners? high-risk drinking behavior by avoiding the negative emotional and behavioral recipient responses often associated with overt strategies. By examining the role of interpersonal processes in the pursuit of identifying and measuring mechanisms of behavior change, the proposed research aligns well with NIH?s cross-cutting program on the Science of Behavior Change. The training environment of the Clinical and Research Institute on Addictions, combined with a knowledgeable and experienced mentorship team (Drs. Leonard, Testa, McCrady, Tucker, Lucke, Derrick), will provide the candidate with unparalleled resources and support during the award period. Furthermore, the proposed training and research experiences will facilitate the development of critical skills and enable the candidate to successfully launch an innovative program of independent research investigating psychosocial mechanisms linking close relationships and problematic alcohol use.